- Remove unused or write-only fields from ulp_mbuf_cb.
- Remove write-only SBUF_ULP_FLAG_COALESCE_OFF flag.
- Failure to allocate ulp_mbuf_cb during rx is a hard error. Panic instead of just freeing the mbuf and pretending nothing happened. The payload in the mbuf is precious because it has been ACK'ed by the TOE. (ulp_mbuf_cb is going to go away soon and so will these potential failures during rx.)